1. Field of the Invention
The present invention relates to a high-quality image input apparatus having a motion compensation function.
2. Related Background Art
In a conventional apparatus for obtaining a high-quality image, an optical axis from an object to be photographed is shifted to make a pixel shift and then a plurality of frames are picked up from the same object. These frames are temporarily recorded on a memory. Thereafter, the frames are synthesized into one image.
FIG. 15 is a block diagram showing a schematic arrangement of a conventional high-quality image input apparatus.
As shown in FIG. 15, the conventional high-quality image input apparatus includes a VAP (Variable Angle Prism) 121 for changing the optical axis for light from an object 111, a lens system 122 for transmitting light 201 from the VAP 121, an image pickup device 113 for imaging the object 111, and an optical axis control device 115 for controlling the VAP 121.
In addition, this apparatus includes a driver 116 for moving the VAP 121 to a predetermined position upon reception of a VAP control signal 204 output from the optical axis control device 115, a VAP position detection device 131 for detecting the position of the VAP 121 and feeding back the position of the VAP 121 as VAP position information 213 to the optical axis control device 115, and a memory selection switch 123 for selecting a plurality of frame memories for recording an image signal 205 from the image pickup device 113.
The apparatus also includes first frame memory (1) 125 to fourth frame memory (4) 128 for recording the image signal 205 from the image pickup device 113, and a read selection switch 124 for selecting a read operation of reading data from the first frame memory (1) 125 to fourth frame memory (4) 128.
The apparatus further includes an image synthesization device 118 for synthesizing a plurality of images read out from the first frame memory (1) 125 to fourth frame memory (4) 128 into one image, and outputting the image as a video signal, a video output terminal 130 for outputting a video signal 210 from the image synthesization device 118 to an external apparatus, and a CPU 119 for controlling the optical axis control device 115, the memory selection switch 123, the read selection switch 124, the image synthesization device 118, and the like.
Referring to FIG. 15, the CPU 119 outputs an optical axis control device control signal 208, a memory selection switch control signal 211, a read selection switch control signal 212, and an image synthesization device control signal 215.
The arrangement of the VAP 121 will be briefly described below. FIG. 12 shows the schematic arrangement of the VAP 121. The VAP 121 is designed to change the optical axis for light from an object in a yawing direction (right and left) and a pitch direction (up and down) by using lenses 301 and 302.
The lens 301 in the yawing direction is moved when a coil driving circuit 307 drives a coil 303 as a voice coil motor under the control of a control circuit 309.
The position of the lens 301 is detected by a position sensor 305 and fed back to the control circuit 309.
In the pitch direction as well, a coil 304, a coil driving circuit 308, and a position sensor 306 operate in the same manner as described above. In general, the VAP 121 is mounted in front of a lens system 310. The VAP 121 can slightly shift an optical axis in the yawing direction (right and left) and the pitch direction (up and down).
The operation of the conventional high-quality image input apparatus will be described next. First of all, the object 111 is imaged by the image pickup device 113, and the resultant data is stored in a memory. In this case, the memory selection switch 123 selects the first frame memory (1) 125. The image signal 205 from the image pickup device 113 is therefore recorded on the first frame memory (1) 125 selected by the memory selection switch 123.
The VAP 121 is then slightly moved in the yawing direction (right) to make a 1-pixel shift in the yawing direction (right). The optical axis control device 115 controls the VAP 121 to shift the image by one pixel in the yawing direction (right).
When the image is shifted by one pixel in the yawing direction (right), the memory selection switch 123 selects the second frame memory (2) 126. In this case, therefore, the image signal 205 from the image pickup device 113 is recorded on the second frame memory (2) 126 selected by the memory selection switch 123.
The VAP 121 is then slightly moved in the pitch direction (down) to make a 1-pixel shift in the pitch direction (down). The optical axis control device 115 controls the VAP 121 to shift the image by one pixel in the pitch direction (down).
When the image is shifted by one pixel in the pitch direction (down), the memory selection switch 123 selects the third frame memory (3) 127. In this case, therefore, the image signal 205 from the image pickup device 113 is recorded on the third frame memory (3) 127 selected by the memory selection switch 123.
The VAP 121 is then slightly moved in the yawing direction (left) opposite the direction in the previous yawing operation to make a 1-pixel shift in the yawing direction (left). The optical axis control device 115 controls the VAP 121 to shift the image by one pixel in the yawing direction (left) opposite the direction in the previous operation.
When the image is shifted by one pixel in the yawing direction (left) opposite the direction in the previous yawing operation, the memory selection switch 123 selects the fourth frame memory (4) 128. In this case, therefore, the image signal 205 from the image pickup device 113 is recorded on the fourth frame memory (4) 128 selected by the memory selection switch 123.
In this manner, the same object is imaged while the object is shifted in the yawing and pitch directions pixel by pixel. The picked-up images are sequentially recorded on the first frame memory (1) 125 to fourth frame memory (4) 128.
Subsequently, the data recorded on the first frame memory (1) 125 to fourth frame memory (4) 128 are sequentially read out through the read selection switch 124. The readout data are synthesized into one image by the image synthesization device 118. The image synthesized by the image synthesization device 118 is output as the video signal 210 from the video output terminal 130.
FIGS. 13A, 13B, 14A, and 14B show object images (the portions painted in gray) formed on the image pickup area of a CCD when the optical path of light from the object is changed using an optical axis changing device, i.e., the relationship between an object image P1 of an original, the image pickup areas of the CCD having a complementary color mosaic filter when the object image P1 of the original is sequentially shifted by one pixel to the right, a lower right hand direction, and down, and object images formed in the image pickup area.
FIG. 13A shows the positional relationship between the image pickup area and the object image P1 of the original.
FIG. 13B shows the relationship between the image pickup area and an object image P2 shifted by one pixel to the right with respect to the object image P1.
FIG. 14A shows the relationship between the image pickup area and an object image P3 shifted by one pixel to the lower right hand direction with respect to the object image P1.
FIG. 14B shows the relationship between the image pickup area and an object image P4 shifted down by one pixel with respect to the object image P1.
Four images of the same object can be obtained by imaging the object while sequentially shifting the object image by one pixel to the right, the lower right hand direction, and down with respect to the object image P1 in the above manner.
Although these four images are obtained by imaging the same object, the pixels of the actually picked-up images are partly different from each other. Note, for example, the upper right pixels of the object images formed in the image pickup area in FIGS. 13A, 13B, 14A, and 14B. The pixel in FIG. 13A is Y (yellow). The pixel in FIG. 13B is C (cyan). The pixel in FIG. 14A is M (magenta). The pixel in FIG. 14B is G (green).
As described above, by imaging the same object while shifting the object image pixel by pixel, four images can be obtained. The number of images in this case is four times larger than that obtained by a conventional image pickup technique. A high-quality image can be obtained by synthesizing these four images into one image.
According to the conventional high-quality image input apparatus, however, owing to the above method of obtaining a high-quality image, if the apparatus moves, it cannot image the same object while accurately shifting the object image pixel by pixel. In addition, since the conventional high-quality image input apparatus has no special measures against motions, if the image pickup unit or the entire apparatus moves, a pixel shift which demands fine control is difficult to perform. For this reason, a stable, high-quality image cannot always be obtained.
The present invention has been made in consideration of the above problem, and has as its object to eliminate the influence of motions by temporarily inhibiting an image signal from being recorded on a recording means when an image pickup unit or an entire image input apparatus moves.
According to a feature of the present invention, there is provided a high-quality image input apparatus for recording an image signal output from an image pickup device on recording means, holding a plurality of images, and synthesizing the images into one image, comprising motion detection means for detecting a motion level of an optical system for inputting light from an object, and control means for performing control to temporarily inhibit the image signal from being recorded on the recording means when a motion detection signal is output from the motion detection means.
According to another feature of the present invention, there is provided a high-quality image input apparatus for recording an image signal output from an image pickup device on recording means, holding a plurality of images, and synthesizing the images into one image, comprising a motion detector for detecting a moving amount of an image by using the image signal picked up by the image pickup device, and detecting a motion level of an optical system up to the image pickup device on the basis of the detection result, and control means for performing control to temporarily inhibit the image signal from being recorded on the recording means, when a motion is detected by the motion detector.
According to still another feature of the present invention, there is provided a high-quality image input apparatus, comprising an optical axis changing device for changing an optical axis for light from an object, an image pickup device for picking up light passing through the optical axis changing device, an optical axis control device for controlling a position of the optical axis changing device, recording means for recording an image signal output from the image pickup device and holding a plurality of images, an image synthesization device for synthesizing the plurality of images held by the recording means into one image, motion detection means for detecting a motion level of an optical system from the optical axis changing device to the image pickup device, and control means for controlling operations of the optical axis control device, the recording means, and the image synthesization device to temporarily inhibit the image signal from being recorded on the recording means when a motion detection signal is output from the motion detection means.
According to still another feature of the present invention, there is provided a high-quality image input apparatus, comprising an optical axis changing device for changing an optical axis for light from an object, an image pickup device for picking up light passing through the optical axis changing device, an optical axis control device for controlling an operation of the optical axis changing device, recording means for recording an image signal output from the image pickup device and holding a plurality of images, an image synthesization device for synthesizing the plurality of images held by the recording means into one image, a motion detector for detecting a moving amount of an image by using an image signal picked up by the image pickup device, and detecting a motion level of an optical system up to the image pickup device on the basis of the detection result, and control means for controlling operations of the optical axis control device, the recording means, and the image synthesization device to temporarily inhibit the image signal from being recorded on the recording means when a motion is detected by the motion detector.
According to still another feature of the present invention, there are provided a high-quality image input apparatus, comprising an optical axis changing device for changing an optical axis for light from an object, an image pickup device for picking up light passing through the optical axis changing device, a motion detector for detecting a moving amount of an image by using an image signal picked up by the image pickup device, an optical axis control device for controlling the optical axis changing device in accordance with information from the motion detector, a driver for moving the optical axis changing device to a predetermined position on the basis of a control signal supplied from the optical axis control device, a position detection device for detecting a position of the optical axis changing device and supplying resultant position data to the optical axis control device, motion detection means for detecting a motion level of an optical system from the optical axis changing device to the image pickup device, recording means for recording an image signal output from the image pickup device and holding a plurality of images, an image synthesization device for synthesizing the plurality of images held by the recording means into one image, and control means for controlling operations of the optical axis control device, the recording means, and the image synthesization device to temporarily inhibit the image signal from being recorded on the recording means when a movement amount of an image which is detected by the motion detector is not less than a predetermined movement amount or a motion detection signal is output from the motion detection means.
According to still another feature of the present invention, there is provided a high-quality image input apparatus, comprising an optical axis changing device for changing an optical axis for light from an object, an image pickup device for picking up light passing through the optical axis changing device, a motion detector for detecting a movement amount of an image and a motion level by using an image signal picked up by the image pickup device, an optical axis control device for controlling the optical axis changing device in accordance with information from the motion detector, a driver for movement the optical axis changing device to a predetermined position on the basis of a control signal supplied from the optical axis control device, a position detection device for detecting a position of the optical axis changing device and supplying resultant position data to the optical axis control device, recording means for recording an image signal output from the image pickup device and holding a plurality of images, an image synthesization device for synthesizing the plurality of images held by the recording means into one image, and control means for controlling operations of the optical axis control device, the recording means, and the image synthesization device to temporarily inhibit the image signal from being recorded on the recording means, when a signal indicating a movement amount of an image which is not less than a predetermined value or a signal indicating a motion level not less than a predetermined level is output from the motion detector.
According to the present invention having the above technical means, when the image pickup unit or the entire image input apparatus moves, the motion detection means detects the motion, thereby temporarily inhibiting an image signal from being recorded on the recording means. Even if the image pickup unit or the entire image input apparatus moves, the influence of the motion can be eliminated.
In addition, according to other features of the present invention, when the image pickup unit or the entire image input apparatus moves, the motion detector detects the motion to temporarily inhibit an image signal 205 from being recorded on a recording means 117. Even if, therefore, the image pickup unit or the entire image input apparatus moves, the influence of the motion can be eliminated. In addition, even if an object moves, the apparatus can temporarily inhibit the image signal 205 from being recorded on the recording means 117.
The above and other objects, features, and advantages of the present invention will be apparent from the following detailed description in conjunction with the accompanying drawings and the appended claims.